Drugs are often delivered directly to target sites of diseased tissue in various contemporary medical procedures. This targeted delivery has proven to be an advantageous approach for treating numerous medical conditions. Using this targeted delivery approach, a controlled dose of the drug may be directly delivered to the target tissue while avoiding or minimizing exposure of other parts of the body to the drug. Also, greater amounts of drug may be delivered to the afflicted parts of the body. In one approach to localized drug delivery, catheter-based, minimally invasive medical procedures are used for deploying intravascular devices such as stents, grafts, or balloon catheters.
One of the problems that can be encountered with such techniques is premature release of the drug while the device is being inserted or deployed. For example, for intravascular devices coated with a drug, the flow of blood around the device can wash away the drug. In addition, insufficient or excessive contact time or pressure can result in inadequate or excessive drug delivery, or vessel injury. Therefore, there is a need for improved methods of delivering drugs to a target site.